Search WhatsApp contacts

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description adds some behavioral context (return type and usability as chat_id) beyond the read-only/idempotent annotations, but it does not specify the exact return format (e.g., array vs object), sorting, or pagination. Annotations already cover safety, so this is acceptable but not fully transparent.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, compact sentence conveying all essential information without redundancy. It is well-structured and easy to parse.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the purpose, matching semantics, and return value. It does not mention error conditions or edge cases (e.g., no results), but for a simple search tool, the information provided is sufficient to use the tool correctly in most scenarios.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already provides descriptive parameter explanations (query as name fragment or phone number, limit as max results). The description adds no additional semantic detail beyond what the schema offers, so it meets the baseline for full schema coverage.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: finding contacts by name or phone number, and specifies the matching behavior (substring vs digit match). It also mentions the returned value (contact_id usable as chat_id), making it distinct from search-related siblings like search_messages.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies usage (when you need to look up a contact), but does not explicitly compare with alternatives or state when not to use it. Given the tool's name and clear purpose, it's evident, but a direct 'use this for contact lookup' would strengthen guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.